Process for bleaching raw stock cotton



Patented Jan. 10, 1939 UNITED STATES 2,143,803 PROCESS FOR BLEAOHING RAW STOCK COTTON Edwin P. Sherman, High Point, N. 0., assignor to The Geo. E. Sherman Company, 1110., Brooklyn, N. Y., a corporation of New York No Drawing. Original a Serial No. 130,417.

tion March 2, 1938,

2 Claims.

This invention relates to bleaching processes, more particularly to a process for bleaching raw stock cotton, and is a division of my co-pending application for patent filed March 11, 1937, Serial Number 130,417.

Standard bleaching processes are relatively complicated and lengthy as, for example, the bleaching of cotton yarn, which involves substantially seven steps, as follows-boiling in caustic, as 2% caustic soda, 1% silicate and 1% sulphonated oil or the like, dropping the above bath and washing in hot water, dropping and running through hypochlorite solution to 2 Tw., dropping and washing in warm water, dropping and scoring in a hydrochloric acid or sulphuric acid solution or the like, dropping and washing in warm water, dropping and washing in water to which is added bluing.

An object of this invention is to provide a bleaching process which is much shorter than standard processes, and involves fewer steps.

Another object is to provide a bleaching process employing a compound containing oxygen and chlorine which process will inhibit the characteristic action of the chlorine upon the fibers without interfering with the action of the nascent oxygen.

Still another object is to provide an improved bleaching process which will be eflicient, even if the material to be bleached contains insoluble oils.

Another object is to provide a bleaching process which will leave the material free of oil stains, chafe marks and so-called niger beads.

Yet another object is to provide a bleaching process which is considerably less expensive than most standard bleaching processes for like material.

Other objects and advantages of the invention will be apparent during the course of the following detailed description thereof.

In the sodium hypochlorite-buffer hereinafter referred to, the buffer may be glues, saponiiied and/or emulsified fats and oils, sulphonated oils, dextrines, glucose, sugar, fatty alcohols, alkali and alkaline salts.

The sodium hypochlorite and buifer may be mixed together in substantially the following proportions:-

Per cent by weight Sodium hypochiorite 95 Mel; 5.

mixture may be employed already mixed, since and 99% while the perpplication March 11, 1937, Divided and this applica- Serial No. 193,604

Percent Soda ash 2 Sodium stearate 1 Sodium hypochlorite-buffer mixture 8 In this treatment of raw stock cotton, the bath last mentioned is maintained at substantially 110 F. for one hour, whereupon the temperature is raised to the boiling point and boiling maintained for substantially forty-five minutes. Thereupon, this bath is dropped, and the material given a good rinse at 120 F., using 1% sodium stearate and bluing, as'desired, in the rinse water. After this last rinse, the material may be extracted.

With the treatment described, the chlorine does not attack the material being bleached, due to the proportions of buffers employed and the temperatures maintained.

Various changes may be made to the forms of the invention herein described, without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. A bleaching process for raw stock cotton, which consists in boiling said cotton in a caustic soda solution, hot rinsing said material for substantially thirty minutes, subjecting said cotton to a bath including soda ash, sodium stearate, sodium hypochlorite and a buffer, said bath being at a temperature of substantially 110 F., maintaining said temperature of said bath for substantially one hour, raising said temperature of said bath to the boiling point and boiling for substantially fory-five minutes, dropping said bath and rinsing said cotton.

2. A bleaching process for raw stock cotton, which consists in boiling said cotton in a caustic soda solution, hot rinsing said material for substantially thirty minutes, subjecting said cotton to a bath including 2% soda ash, 1% sodium stearate, 8% sodium hypochlorite buffer mixture, said bath being at a temperature of substantially 110 F., maintaining said temperature of said bath for substantially one hour, raising said temperature of said bath to the boiling point and boiling for substantially forty-five minutes, dropping said bath and rinsing said cotton.

EDWIN P. SHERMAN. 

